Compound 2-cycloodecyl-6-t-butyl-p-cresol



April 1953 J. E. SHERIDAN ETAL 3,379,775

COMPOUND Z-CYCLODODEGYL 6-T-BUTYLPCRESOL Filed Dec. 10, 1963 ADDINGSULFURIC ACID CATALYST TO P-CRESOL ADDING CYCLODO- DECENE AND cou-DENSING SEPARATELY REMOVING UNCONVERTED P-CRESOL AND CYCLODODECENEOBTAINING Z-CYCLO- DODECYL- P-CRESOL ADDING SULFURIC ACID CATALYST FORFURTHER ALKYLATION ADDING ISOBUTYLENE AND HEATING SEPARATELY RECOVE RING2- CYCLODODECYL P- CRESOL REMOVING Z-CYCLO- DODECYL-G-T- BUTYL-P-CRESOL.

OH a 3 12 "23 INVENT OR JOHN E. SHERIDAN ERIC 8. HOTELLING BY SEMMES ANDSEMMES ATTORNEY United States Patent O 3,379,775 COMPOUND2-CYCLODODECYL- 6-t-BUTYL-p-CRESOL John E. Sheridan, Chesapeake, Va.,and Eric B. Hotelling, Spring Valley, N.Y., assignors to VirginiaChemicals, a corporation of Maine Filed Dec. 10, 1963, Ser. No. 329,5121 Claim. (Cl. 260-624) The present invention relates to a rubberanti-oxidant composition and method for synthesis.

There are numerous commercially acceptable rubber anti-oxidantcompositions, including American Cyanamid Rubber Anti-oxidantComposition 2246 and Shell Oil Companys trademarked product Ionol.However, such rubber anti-oxidants are expensive to manufacture andoftentimes are dangerously volatile or have staining effects on rubber.Staining effects are particularly undesirable, of course, in themanufacture of white rubber. Applicants have developed an economicalmethod for synthesis of a rubber anti-oxidant composition which is bothnon-volatile and non-staining. This anti-oxidant composition is readilysynthesized from p-cresol, isobutylene and cyclododecene to yield2-cyclododecyl-6-t-butylp-cresol which is a non-staining, non-volatileanti-oxidant for rubber having the desired aging characteristics.

Accordingly, it is an object of invention to provide a method for thesynthesis of a rubber anti-oxidant composition at low cost.

Another object of the invention is to provide a method for synthesis ofa rubber anti-oxidant composition which is non-staining andnon-volatile.

Yet additional objects of invention will become apparent from theensuing specification and attached drawing which is a flow-sheet,illustrating synthesis according to the present method.

In development of the present method, applicants studied various organicproducts derived from p-cresol and 2,4-xylenol. In this study cyclic Cunsaturated hydrocarbons, including cyclododecene and cyclododecatrienewere condensed with p-cresol in the ortho-position. The otherortho-position carried a t-butyl group. The C cyclic and straight chainunsaturated hydrocarbons were also condensed with 2,4-xylenol in theortho-position. Examples of the hydrocarbons employed are n-dodecene- 1,triisobutylene, cyclododecene and cyclododecatriene. Where yields of thevarious syntheses were acceptable,

Patented Apr. 23, 1968 ice the products were tested aspen-stainingrubber antioxidants. Consequently, there was developed a non-stainingrubber anti-oxidant having properties, equal to or better thancommercially accepted anti-oxidants and synthes zed at lower cost.

According to the present method, 216 grams of p-cresol were condensed bythe dropwise addition of 332 grams of cyclododecene at 140 C. at therate of 7.4 grams per minute, the condensation reaction being catalyzedby the addition of 6.5 grams of sulfuric acid. From this reaction therewas recovered 71.3%. of unconverted p-cresol and 95.8% of unconvertedcyclododecene. There was a 61% yield of 2-cyclododecyl-p-cresol, basedon converted pcresol. This 2-cyclododecyl-p-cresol composition has aboiling point of 171 C. at 1.5 mm.

Eighty-three grams of the 2-cyclododecyl-p-cresol were butylated byadding 51 grams of isobutylene and heating in an autoclave from to 150C. for fifty minutes. This reaction was catalyzed through the additionof 0.8 grams of sulfuric acid. From this reaction there was recovered16.4% unconverted 2-cyclododecyl-p-cresol and a 91.4% yield based onconverted starting material of 2-cyclododecyl-6-t-butyl-p-cresol:

(CH3): C 0 21123 This 2-cyclododecyl-6-t-butyl-p-cresol composition hada boiling point of 158-164 C. at 0.3 mm.

Test results achieved independently by Smithers Laboratories of Akron,Ohio, were based on the following test formula:

TEST FORMULA TENSION TESTING OF VULCANIZED RUBBER Unaged physicals-Tested at room temperature (ASTM D412-51T-AS TM D599-55) and rubbercured with 2-eyclododecyl-fi-t-butyl-p-cresol as an anti-oxidant Modulusof elasticity at- Lbs/Sq. In. Percent Percent Shore T-50 274 F. TensileElong. Set Hardness C.

Cure 300% 500% Test Formula containing2,2-methylene-bis-(4-methyl-fi-t-buytlphenol) Test Formula containing2,6-di-t-bntyl-p-eresol Test Formula containing2-oyelododecyl-G-t-butyl-p-cresol 3 The modulus of elasticity is definedin ASTM Test Method E6-54T (page 1683) and is given as the ratio ofstress to corresponding strain below the proportional limit. The modulusat 300% and 500% represents the 4 The T-SO test, which is described inASTM Standard Test Method B599-55, is carried out as follows:

A test specimen 1 to 2 in. in length and having a uniform cross-sectionis immersed in a liquid bath at 20 C.,

ratio of stress to the corresponding strain in tests in which 5stretched to an elongation of 75 percent or more of the alength of 1"distance marked on a-specimen is stretched breaking elongation, and heldfor 5 min. It is then until the bench marks are 4" (300%) apart or 6"plunged into a bath of acetone at 50 to 70 C., 500%) apart. The tensiletest procedure used is deheld until cool, and released. The rubber willshow pracscribed in ASTM Testing Method D4l251"I, pages 1129 tically noelastic retraction. The temperature is then and 1131. m raised slowlyand the sample is found to contract, taking T 50 values given in thetable of data by Smithers a definite length at a given temperature. Thetempera- La'boratories refer to a test value gotten by determinture onthe centigrade scale at which the elongation of ing the extent orphysical state of cure of a rubber comthe sample becomes equal toone-half the initial elongapound by measuring the temperature at whichit recovers tion is the T-50 value. its elasticity when it is stretchedat room temperature, There are presented below comparative test resultsfrozen at a sufficiently low temperature to cause it to achieved fromOxygen Bomb Aged Physicals: Samples lose its elastic properties and thengradually warmed. aged 168 hrs./300# .02/70" C.

274 F. Modulus at Lbs/Sq. In. Percent Percent Shore Percent Cure TensileElong. Set Hardness Weight 300% 500% Change Test Formula containing2,2-methylene-bis-(4-methyl-6-t-butylphenol) Test Formula containing2,6-dl-t-butyl-p-cresol Test Formula containing2-cyclododecyl6-t-butyl-p-cresol AVERAGE OF THE 30 AND 45 CURE DATAModulus at- Lb sf/Sq. In. Percent Percent Shore Percent PercentctOriglnaensile Elong. Set Hard- Weight 300% 500% ness Change Ten. Elong.

Test Formula containing 2,2'-methylene bis-(4-methyl-6-t-butylpheno1)Test Formula containing 2,6-di-t-butyl-p-cresol Test Formula containing2-cyclododecy16-t-butyl-p-cresol PHYSICALS-SAMPLES AGED 14 DAYS AT 158F.HOT AIR OVEN 274 F. Modulus a't- Lbs/Sq. In. Percent Percent ShorePercent Cure Tensile Elong. Set Hardness Weight 300% 500% Change TestFormula containing 2,2'-methylcne bis-(4-methyl-6-t-butylphenol) AVERAGEOF THE 30 AND 45 CURE DATA [Hot air oven aged 14 days/158 F.]

Modulus at-- Lbs/Sq. In. Percent Percent Shore Percent Percent ofOriginal Tensile Elong. Set Hard- Weight 300% 500% ness Change Ten.Elong.

Test Formula containing 2,2methylene bis-(4-rnethyl-6-t-butylphenol)Test Formula containing 2,6-dl-t-buty1-p-cresol Test Formula containing2-cyclododeeyl-fi-t-butyl-p-eresol TENSILE RETENTION Aged Test FormulaContaining- Uuaged Oxygen Bomb Hot Air Oven Tensile Elong. TensileElong. Tensile Elong.

3, 000 685 78 94 111 93 2,2-methylene bls-(-methyl' Y fi-t-butylphenol)2,945 680 106 93 123 93 2,6-di-tbutyl-p-cresol. 3, 155 655 90 98 105 972-cyc1ododeeylo-t-butyl-pcresol 2, 900 665 103 96 122 98 (Ozone exposure50 parts per 100 million; 100 F. at 20% elongation; exposure period 24hours. All samples showed some ozone cracking after 24 hours exposure.)

The samples cured 60 minutes at 274 F. were exposed for periods from 24to 48 and 72 hours to the ultraviolet of the weatherometer and werefound to be nondiscoloring.

Also, 60-minute cure samples were dipped in white lacquer and exposed toultra-violet light for periods of 24, 48 and 72 hours. No staining wasfound in these samples.

The present synthesis can be achieved from toluene via p-cresol at a rawmaterial cost of 15 to 17 cents per pound. There is no loss ofanti-oxidant effect and better color property in white rubber isprovided. According to the related methods and using sulfuric acid as acatalyst, the following compositions have been obtained, yet have beenrejected because of their poor staining characteristics or low activity:2-cyclododecadienyl-p-cresol; 6-sec-dodecyl-2,4-xylenol;6-cyclododecyl-2,4-xylenol; and 6 -cyc1ododecadienyl-2,4-xy1eno1.

The composition 2-cyclododecyl-6-t-butyl-p-cresol is unique because itshows anti-oxidant activity where related compositions do not.

Manifestly, the conditions of synthesis including substitution ofcatalysts and variation in temperature, pressures, and preparations ofreactants may be employed without departing from the spirit and scope ofinvention,

FOREIGN PATENTS 758,474 10/1956 Great Britain.

BERNARD HELFIN, Acting Primary Examiner.

LEON ZITVER, Examiner.

W. LONE, Assistant Examiner.

1. THE COMPOUND 2-CYCLODODECYL-6-T-BUTYL-P-CRESOL